1. Field of the Invention
The present invention relates generally to the field of industrial and commercial trash bins or containers and, more particularly, to large, wheeled industrial and commercial waste and trash bins or containers commonly known in the industry as "roll-off boxes".
2. Background Discussion
A number of types of large, wheeled commercial and industrial waste and trash bins or containers are in wide use, at least in the United States. One of these types is the ubiquitous "front-load container," which is typically about six feet wide, about four feet long and about five feet deep, and usually has a hinged cover or lid. This type of trash bin is ordinarily constructed having elongate, rectangular channels underneath, or on the sides, into which fit the projecting "tines" of fork lifts or fork lift-type apparatus on trash trucks. When trash is to be emptied from these containers, a trash truck, with its fork lift-type apparatus on the front of the truck, lifts the front load container up and over the top of the truck's cab and then pivots the container rearwardly so that it dumps its contents into a larger trash container on the truck. Such front load containers are most commonly used by stores, restaurants and other business establishments because, while large enough to hold a considerable amount of trash and waste, they are small enough to fit into alleys and the like. Another type of container is a type called "rent-a-bin" container which is commonly used for yard clean-up and is typically carried and delivered in a nested relationship with other similar containers.
Another major type of commercial and industrial waste and trash containers, and the type to which the present invention is particularly directed, is larger than a front load container, the bin or box of which is about eight feet wide and about sixteen feet long. For reasons which will become apparent, such containers or bins are typically referred to as "roll-off boxes." Such roll-off boxes usually have two standard depths: one depth is about three feet and the other depth is about six feet. Since both depths of roll-off boxes have about the same trash weight capacity, which is dependent upon the ability of an associated "roll-off truck" to pick up the loaded boxes and upon state and/or local restrictions, the depth of roll-off box selected depends upon the weight of trash or other materials to be dumped therein. For example, the three foot deep roll-off boxes are typically most efficiently used for heavy trash, such as as broken masonry, concrete and asphalt; earth; bricks and tile. The six foot deep roll-off boxes are typically constrained to receiving lighter-weight materials, such as scrap lumber, plasterboard, broken shingles, and tree branches and trimmings. As can be appreciated from the large capacity of roll-off boxes, they are most commonly used at construction and building demolition sites; although, the six foot deep roll-off boxes may be used for neighborhood clean-up projects in urban or suburban areas. To enable their easy emptying and also their filling, roll-off boxes are typically constructed with wide-swinging doors at one end, which may be considered the rear end of the boxes.
Roll off boxes are typically constructed having steel wheels several inches in diameter and several inches wide mounted at their lower corners so that the boxes can be rolled longitudinally along the ground and easily on-loaded and off-loaded onto associated roll-off trucks. Such trucks have a power-tiltable flat bed with a power winch at the front (cab) end thereof. When a roll-off box is to be on-loaded onto the roll-off truck, for example, so that, when empty, the box can be delivered to an intended use site or so that, when filled, it can be hauled to a dumping site, the roll-off truck backs up to the forward end of the box (that is, the end of the box without doors). The front end of the truck bed is then tilted upwardly until the rear end of the bed is near the ground or pavement. A cable from the power winch is attached to the forward end of the roll-off box to on-load onto the truck and the box is winched up onto the truck bed, the box rolling on its wheels. When the box is winched all the way onto the truck bed, the box is locked in place and the truck bed is tilted back to its normal, horizontal position. Empty roll-off boxes are off-loaded from the roll-off truck at a storage facility or at an intended use site by reversing the above-described on-loading procedure. To dump the contents of a loaded roll-off box (which is loaded on a roll-off truck) at a dumping site, such as a sanitary land fill, the rear doors of the container are opened and the bed of the roll-off truck is tilted so that the contents of the roll-off box slide out onto the ground, the combination roll-off box and roll-off truck functioning as a dump-truck.
A disadvantageous economic factor associated with the use of the shallower, three foot deep roll-off boxes is that such boxes, even though only about half the height of the six foot deep roll-off boxes, still have had to be delivered to use sites in the empty condition one at a time. Also when empty or lightly-loaded shallow roll-off boxes had to be otherwise moved around they have heretofore had to be moved one at a time. This one-at-a-time transporting of shallow roll-off boxes has been required even though the empty weight of such boxes is substantially less than the carrying capacity of the roll-off trucks, which are also used to transport the deeper roll-off boxes. Moreover, shallow roll-off boxes have heretofore required as much ground storage space as the deeper roll-off boxes, even though their volumetric capacity is only about half that of the deeper boxes.
It is, therefore, an objective of the present invention to enable shallow (that is, three foot deep) roll-off boxes to be stacked one upon another to a height of about three boxes without the use of any equipment other than a conventional roll-off truck, and to enable the simultaneous carrying of up to about three shallow roll-off boxes in a stacked condition on a single roll-off truck. It is a further objective of the present invention to provide a kit for enabling the modifying of existing shallow roll-off boxes so that they can be easily stacked one upon another by the use of only a conventional roll-off truck.